DOE OSTI2020
YbF3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Yb3+ is bonded to twelve F1- atoms to form YbF12 cuboctahedra that share corners with four equivalent YbF12 cuboctahedra, corners with eight equivalent FYb4F8 cuboctahedra, corners with sixteen equivalent FYb4F4 tetrahedra, edges with eight equivalent YbF12 cuboctahedra, edges with eight equivalent FYb4F4 tetrahedra, faces with four equivalent YbF12 cuboctahedra, and faces with six equivalent FYb4F8 cuboctahedra. There are eight shorter (2.41 Å) and four longer (2.59 Å) Yb–F bond lengths. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to four equivalent Yb3+ and four equivalent F1- atoms to form distorted FYb4F4 tetrahedra that share corners with eight equivalent YbF12 cuboctahedra, corners with eight equivalent FYb4F8 cuboctahedra, corners with eight equivalent FYb4F4 tetrahedra, edges with four equivalent YbF12 cuboctahedra, edges with four equivalent FYb4F8 cuboctahedra, edges with twelve equivalent FYb4F4 tetrahedra, and faces with six equivalent FYb4F4 tetrahedra. All F–F bond lengths are 2.41 Å. In the second F1- site, F1- is bonded to four equivalent Yb3+ and eight equivalent F1- atoms to form distorted FYb4F8 cuboctahedra that share corners with four equivalent FYb4F8 cuboctahedra, corners with eight equivalent YbF12 cuboctahedra, corners with sixteen equivalent FYb4F4 tetrahedra, edges with eight equivalent FYb4F8 cuboctahedra, edges with eight equivalent FYb4F4 tetrahedra, faces with four equivalent FYb4F8 cuboctahedra, and faces with six equivalent YbF12 cuboctahedra.